The link you have posted just comes up with a white page with
Site4All in the top left corner and when you click it you go to this site
http://www.site4all.nl/.
Here is a link to help set up Virginmedia's own proxy to access the site.
http://www.cableforum.co.uk/board/34773822-post18.html
Or you can try
http://www.opendns.com/